21418753 has 2 divisors, whose sum is σ = 21418754. Its totient is φ = 21418752.

The previous prime is 21418751. The next prime is 21418763. The reversal of 21418753 is 35781412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20684304 + 734449 = 4548^2 + 857^2 .

It is a cyclic number.

It is not a de Polignac number, because 21418753 - 2¹ = 21418751 is a prime.

Together with 21418751, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21418751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10709376 + 10709377.

It is an arithmetic number, because the mean of its divisors is an integer number (10709377).

Almost surely, 2^21418753 is an apocalyptic number.

It is an amenable number.

21418753 is a deficient number, since it is larger than the sum of its proper divisors (1).

21418753 is an equidigital number, since it uses as much as digits as its factorization.

21418753 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6720, while the sum is 31.

The square root of 21418753 is about 4628.0398658611. The cubic root of 21418753 is about 277.7141835871.

The spelling of 21418753 in words is "twenty-one million, four hundred eighteen thousand, seven hundred fifty-three".